Given, height of window, h=1.8m Initial velocity, u=8m∕s
We know that, v2−u2=2 as 0−(8)2=2×(−10)s ⇒s=3.2m Total distance =3.2+1.8m Time for total descent, v=u+at 10=0+(10)T ⇒T=1s Time taken for the stone to reach the height of window, v=u+at 0=8−10(t) ⇒t=0.8s ⇒ Time to cross the window, t2=T−t1 =1−0.8 =0.2s
